The present invention relates to containers for cooling/refrigerating perishable goods and particularly but not exclusively to containers for maintaining the temperature of perishable goods in transit.
Known cryogenic refrigeration systems for transporting perishable food stuff comprise heavily insulated liquid storage tanks which are capable of holding liquid cryogen at several atmospheres pressure. Usually, a distribution system is provided which utilises the pressure within the storage tank to generate a spray of cryogen within a container to reduce the temperature within the container and that of any perishable goods therein. These systems are common in vehicular refrigerated traitors, or xe2x80x9creefersxe2x80x9d either instead of or in combination with a mechanical refrigeration unit.
Containers are also used to transport produce which are designed to fit an aircraft hold. One such container makes use of dry ice stored within the container coupled with a battery driven fan which provides a degree of temperature control for the produce in transit. However, this solution to the transit of perishable goods by air is wasteful since much of the heat available from the liquid carbon dioxide is lost in transforming to dry ice and the dry ice itself continues to evaporate because of heat leak thereby needing to be renewed frequently.
It is an aim of the present invention to provide a container for cooling/refrigerating produce without the need for an external power source.
According to the present invention, a container for cooling/refrigerating produce comprises at least one panel made from metal foam for storing a cryogenic fluid under pressure and means for discharging said fluid into the container in order to reduce/maintain the temperature within the container.
Preferably the cryogenic fluid is liquid carbon dioxide and a valve is provided within the container, the operation of which valve controls the discharge of the liquid carbon dioxide according to the temperature within the container.
Preferably the valve is actuated by means of a signal from a temperature sensor located within the container.
In a preferred embodiment the container is provided with an envelope or cover of insulating material.